Tecnologia em Metalurgia, Materiais e Mineração
https://www.tecnologiammm.com.br/article/doi/10.4322/tmm.2013.003
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

ESTUDO NUMÉRICO DA INFLUÊNCIA DE PROPRIEDADES DE AMOLECIMENTO E FUSÃO NA CINÉTICA DE FORMAÇÃO DE (CAFE2O4-CA2FE2O5) NA SINTERIZAÇÃO DE MINÉRIO DE FERRO

NUMERICAL EVALUATION OF THE EFFECTS OF SOFT-MELTING PROPERTIES ON THE KINETIC OF (CAFE2O4-CA2FE2O5) FORMATION IN THE IRON ORE SINTERING PROCESS

Castro, José Adilson de; França, Alexandre Bôscaro; Guilherme, Vagner Silva; Sazaki, Yasushi

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Resumo

O presente trabalho apresenta um modelo matemático capaz de prever a influência das propriedades de amolecimento e fusão da mistura de matérias primas na cinética de formação dos constituintes cálcio ferrita e dicálcio ferrita na sinterização de minério de ferro. O modelo é baseado na solução simultânea das equações de transporte de Momentum, energia e espécies químicas formuladas para sistemas multifásico e multicomponente, acoplado à cinética de reações químicas e transformações de fases que ocorrem no interior da esteira de sinterização. A solução numérica é obtida utilizando-se o método de volumes finitos validado com resultados de monitoramento de uma planta industrial de sinterização. Os resultados indicam que as temperaturas de início de amolecimento, contração volumétrica e intervalo de fusão são os principais parâmetros a serem controlados visando obtenção de formação de fase líquida que confere resistência mecânica e redutibilidade adequadas ao sínter. Neste estudo confirma-se que matérias primas com alto ponto de amolecimento e fusão combinado com alta contração volumétrica e grande intervalo de temperatura da zona pastosa podem diminuir até 20% o volume de fase líquida formada e, consequentemente, diminuir em mais de 30% a formação de cálcio ferritas o que deterioraria consideravelmente as propriedades finais do sínter.

Palavras-chave

Sinterização, Minério de ferro, Modelagem matemática, Cinética de formação

Abstract

This paper presents a mathematical model able to predict the influence of soft-melting properties of the blend of raw materials used in the iron ore sintering process in the kinetic formation of calcium ferrite and di-calcium ferrite constituents. The model is based on the simultaneous solution of transport equations of Momentum, energy and chemical species in multiphase multicomponent systems coupled with the chemical reactions kinetics and phase transformations that occur within the sinter bed. The numerical solution is obtained using the finite volume method and the model is validated using monitoring data from an industrial scale sintering plant. After validation, the model was used to predict processing conditions using raw materials with different soft-melting properties. Results indicate that the temperatures of starting soft-melting, shrinkage and melting range are the main parameters to be controlled in order to attain liquid phases formation responsible to confer good mechanical and reducibility properties for the sinter product. In this study was found that raw materials with high soft-melting temperature and wilder temperature of mushy zone could decrease up to 30% the calcium ferrites formation and hence deteriorates the metallurgical properties of the sinter.

Keywords

Sintering, Iron ore, Mathematical modeling, Kinetic formation

Referências

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